This deserved a separate thread because AndreasPassat and I are discussing an issue that is puzzling. He's convinced that there are two orings, and I only have one. I have one on the old one I removed, and only one came with the new one I'm about to install. It mounts on the outside of the thermostat (so you can see it when the thermostat is inserted). I didn't have any o-rings behind it, nor did the replacement thermostat come with two o-rings (just the same as I removed). What the heck is going on? AndreasPassat is always spot on, so I don't know what the heck to think. I didn't see anything fly out when I pulled the old one. I can look around. Makes no sense.